I love love love this product. I'm a beginner violin player and this has helped me a lot in tuning my violin at home when my teacher is not around. It has also helped me to know if my fingers are in the correct spot when playing. It's very accurate. I have tested it against our piano. It's small enough that it's barely noticeable. The digital display is very clear. It's turns to a different color when you are flat or sharp on the key. It's fits perfectly on my violin. And it's adjustable so it should fit in any size violin. The display angle can also be adjusted so that it faces you in a comfortable view. The only thing I wish I could change is that it automatically turns off after a while. I have to keep turning it back on. I wish there's a feature to where to can pick "auto" for automatic shut off or "on" if you want it to stay on the whole time you are playing. Other than that, excellent product especially for a beginner like me.